N.QN  CIRCULATING 

CHECK  FOR  UNBOUND 
CIRCULATING  COPY 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  271 


AN  EXPERIMENT  IN  SELECTING  CORN 

FOR  YIELD  BY  THE  METHOD  OF 

THE  EAR-ROW  BREEDING  PLOT 

BY  LOUIE  H.  SMITH  AND  ARTHUR  M.  BRUNSON 


URBANA,  ILLINOIS,  NOVEMBER,  1925 


SUMMARY 

The  possibility  of  improving  the  yield  of  corn  by  continuous  ear- 
row  selection  has  been  rather  generally  assumed,  and  no  little  effort 
has  been  expended  in  attempting  to  produce  higher  yielding  strains  thru 
one  or  another  of  the  various  possible  modifications  of  this  method  of 
breeding. 

The  remarkable  results  in  altering,  thru  ear-row  breeding,  certain 
special  characters  such  as  protein  and  oil  content  of  the  grain  and 
height  of  ear  on  the  stalk,  led  to  the  assumption  that  yield  might  be  in- 
fluenced by  a  similar  process  of  selection.  In  view  of  a  doubt  as  to 
whether  breeding  for  these  special  characters  and  breeding  for  yield 
represent  truly  analagous  cases,  it  seemed  desirable  to  secure  some 
actual  experimental  evidence.  To  this  end  a  test  was  made  covering 
ten  years  of  selection  for  yield  by  the  method  of  the  ear-row  breed- 
ing plot. 

The  results  of  this  investigation  led  to  the  conclusion  that  the 
simpler  method  of  mass  selection,  that  is,  picking  seed  ears  from  stand- 
ing stalks  in  the  field,  ordinarily  will  be  just  as  effective  in  improving 
the  yield  as  the  more  complicated  method  of  continuous  ear-row 
breeding. 

The  experiment  involved  the  use  of  an  unnamed  variety  of  no  par- 
ticular breeding  but  adapted  to  the  region.  A  high-yield  and  a  low-yield 
breeding  plot  were  founded  upon  the  basis  of  the  relative  productive- 
ness of  the  seed  ears  as  determined  by  a  preliminary  ear-row  test. 
Continued  selection  in  these  two  opposite  directions  resulted  in  a 
marked  separation  of  the  two  strains  with  respect  to  yield.  The  High 
Yield  strain,  however,  did  not  significantly  surpass  in  yield  a  control 
strain  propagated  from  the  original  stock  by  careful  field  selection 
without  pedigree  breeding. 

It  appears,  therefore,  that  the  difference  in  productiveness  between 
the  High. Yield  and  Low  Yield  strains  was  brought  about  mainly  thru 
a  decrease  in  the  Low  Yield  strain. 


AN  EXPERIMENT  IN  SELECTING  CORN 
FOR  YIELD  BY  THE  METHOD  OF  - 
THE  EAR-ROW  BREEDING  PLOT     .;_ 

By  LOUIE  H.  SMITH  AND  ARTHUR  M.  BRUNSON* 

THE  PROBLEM 

Many  years  ago  this  Experiment  Station  demonstrated  in  a  strik- 
ing way  the  effect,  on  various  special  characters  in  corn,  of  ear-to-row, 
or  "ear-row,"  selection.  By  this  method  the  chemical  composition  of 
the  grain  has  been  so  modified  that  strains  of  high  and  of  low  protein 
content,  as  well  as  of  high  and  of  low  oil  content,  have  been  produced 
from  a  single  original  variety.8  Likewise,  habits  of  growth  have  been 
influenced  to  produce  strains  bearing  ears  high  on  the  stalk  and  low 
on  the  stalk,  according  to  the  direction  of  the  selection,  and  in  similar 
manner  a  strain  bearing  erect  ears  and  another  bearing  declining  ears 
have  been  produced  by  selection  in  opposite  directions.9 

Following  these  demonstrations  the  question  arose  whether  the 
productive  capacity  of  the  corn  plant  might  not  likewise  be  modified 
by  a  similar  process  of  continuous  selection.  A  number  of  seed  corn 
growers,  assuming  that  this  would  be  the  case,  undertook  to  improve 
their  varieties  by  systematic  ear-row  selection.  After  working  along 
this  line  for  a  few  years,  some  of  these  breeders  became  doubtful 
whether  they  were  making  any  progress.  Unfortunately,  they  had  failed 
for  the  most  part  to  plan  a  check  by  which  a  comparison  of  the  selected 
strains  could  be  made  with  the  original  unselected  stock. 

In  view  of  the  dearth  of  experimental  evidence  at  the  time  the 
present  investigation  was  undertaken,  as  to  the  efficiency  of  the  ear-row 
system  as  a  means  of  improving  the  yield  of  corn,  it  seemed  desirable 
to  test  the  matter  by  a  carefully  checked  experiment.  This  bulletin 
presents  the  data  obtained  in  an  experiment  at  this  Station  extending 
over  a  period  of  ten  years  and  includes  a  brief  review  of  work  done 
at  other  stations. 

INVESTIGATIONS  AT  OTHER  EXPERIMENT  STATIONS 

Published  results  of  investigations  dealing  with  this  particular  phase 
of  corn  breeding  are  rather  meager,  but  a  summary  of  the  experience  of 
different  investigators  would  seem  to  show  that  the  ear-row  system  of 
selection  which  has  been  so  effective  in  influencing  special  characters  in 

•LouiE  H.   SMITH,   Chief   in  charge  of  Publications   of  the  Soil   Survey,    (formerly   Chief   in  Plant 
Breeding);    ARTHUR  M.  BRUNSON,   formerly  Associate   in  Plant  Breeding. 


567 


I 


568  BULLETIN  No.  271  [November, 

corn  does  not  apply  with  the  same  success  to  that  exceedingly  intricate 
complex  of  characters  that  determines  yielding  capacity. 

Montgomery,5  working  at  the  Nebraska  Experiment  Station,  re- 
ported after  the  first  few  years  of  an  ear-row  breeding-plot  experiment 
an  apparent  gain  by  the  use  of  seed  selected  in  this  way  over  seed  rep- 
resenting the  original  stock.  According  to  a  later  account  of  this  same 
experiment  by  Kiesselbach,3  however,  it  appears  that  the  gain  thus  ob- 
tained in  the  earlier  years  of  the  work  was  subsequently  lost. 

Noll6  described  some  experiments  at  the  Pennsylvania  Station  in 
which  he  compared  yields  of  seed  produced  by  ear-row  breeding  with 
ordinary  field-grown  seed  of  the  same  variety.  The  results  on  the  whole 
indicated  no  consistent  gains  by  the  use  of  breeding-plot  methods. 

Hume,2  of  the  South  Dakota  Station,  presented  data  based  upon 
relative  yields  of  rows  within  the  breeding  plot,  which  apparently  indi- 
cated to  him  that  some  improvement  attributable  to  the  ear-row  selec- 
tion had  been  effected;  but  when  seed  from  these  same  breeding  plots 
was  brought  into  a  variety  test  series,  the  comparisons  failed  to  show 
any  convincing  evidence  of  such  improvement. 

More  favorable  results  from  a  somewhat  similar  method  of  breed- 
ing are  shown  by  Williams  and  Welton,12  of  the  Ohio  Station.  Of  twenty 
strains  produced  under  a  breeding-plot  system,  eighteen  yielded  more 
than,  the  parent  stock,  the  increases  ranging  from  about  1%  bushels  to 
11  bushels  an  acre. 

Hayes  and  Alexander,1  of  the  Minnesota  Station,  have  recently 
published  an  account  of  some  experiments  on  the  relative  efficiency  of 
different  methods  of  seed-corn  selection.  In  these  experiments  Mont- 
gomery's method  of  preliminary  ear-row  testing  and  Williams'  method 
are  compared  with  simple  mass  selection  from  the  field.  The  authors 
express  the  following  conclusion:  "There  seems  to  be  little  or  no  value, 
from  the  farmer's  standpoint,  of  using  the  ear-to-row  plan.  Under  any 
circumstances  its  continued  use  appears  undesirable." 

After  a  careful  summary  of  the  various  published  investigations, 
Richey,7  of  the  U.  S.  Department  of  Agriculture,  came  to  the  following 
conclusion:  "It  seems  probable  that  the  yield  of  an  entirely  unselected 
or  unadapted  variety  could  be  improved  by  a  few  years  of  intelligent 
ear-to-row  selection.  However,  in  view  of  the  expense,  the  uncertainty 
with  which  larger  yields  have  been  obtained,  and  the  small  increases 
secured  during  a  series  of  years  in  the  most  favorable  cases,  so  far  there 
appears  to  be  little  to  recommend  ear-to-row  breeding  as  a  practical 
method  of  corn  improvement." 

PLAN  OF  THE  PRESENT  INVESTIGATION 

In  brief,  the  plan  adopted  in  the  present  investigation  included  the 
following  points:  (1)  the  use  of  a  well-adapted  local  strain  which,  in 
its  immediate  history  at  least,  had  not  been  subjected  to  systematic 


X 


1925~\  SELECTING  CORN  FOR  YIELD  569 

selection;  (2)  the  use  of  a  foundation  stock  extensive  enough  to  insure 
a  reasonably  adequate  sample  of  the  various  types  represented  in  that 
strain;  (3)  provision  for  the  continuation  of  a  composite  sample  of  all 
foundation  ears  by  mass  selection  in  an  isolated  field,  in  order  to  have 
a  basis  for  comparison;  (4)  the  determination  of  the  relative  potential 
productive  capacity  by  means  of  a  preliminary  ear-row  test  of  all 
foundation  ears;  (5)  the  employment  of  an  isolated  "High  Yield"  ear- 
row  breeding  plot  originated  from  the  remnant  seed  of  the  forty  rows 
showing  highest  production  in  the  preliminary  ear-row  test;  (6)  the 
employment  of  a  corresponding  "Low  Yield"  ear-row  breeding  plot 
started  from  the  remnant  seed  of  the  forty  rows  showing  lowest  produc- 
tion in  the  preliminary  ear-row  test;  (7)  a  comparison  of  annual  yields 
of  replicated  plots  planted  from  seed  composites  taken  from  their  re- 
spective breeding  plots,  in  this  way  measuring  the  effectiveness  of  the 
selection. 

THE  FOUNDATION  STOCK 

For  the  purpose  of  this  experiment  several  bushels  of  ear  corn  of 
an  unnamed  yellow  variety  were  obtained  from  a  near-by  farm.  During 
the  known  history  of  the  corn  it  had  had  no  particular  breeding  other 
than  crib  selection  of  viable  seed  ears,  and  had  been  subjected  to  no 
close  selection  for  type.  Nine  hundred  ninety  ears  were  finally 
taken  from  the  lot  to  represent  the  original  stock. 

THE  NON-PEDIGREE  STRAIN 

In  order  to  measure  progress  in  improving  corn  it  is  necessary  that 
the  selected  strain  be  compared  from  year  to  year  with  the  original 
stock.  For  the  purpose  of  perpetuating  the  foundation  strain,  a  com- 
posite lot  of  seed  representing  all  the  original  990  ears  was  taken.  This 
strain  was  grown  each  year  in  an  isolated  field  of  several  acres  and 
propagated  by  simple  mass  selection.  Each  fall  enough  good  seed  ears 
were  selected  from  the  standing  corn  to  plant  the  field  the  following 
year.  This  strain  was  designated  as  the  Non-pedigree  strain,  as  dis- 
tinguished from  the  High  Yield  and  Low  Yield  strains  to  be  produced 
under  pedigree*  selection. 

THE  HIGH  YIELD  AND  Low  YIELD  STRAINS 
The  Preliminary  Ear-row  Test 

Seed  from  each  of  the  original  990  ears  was  planted  in  an  individual 
ear-row  in  1911  to  determine  its  relative  yielding  capacity  as  a  basis  for 
the  selection  of  remnant  seed  with  which  to  start  the  High  Yield  and 
the  Low  Yield  breeding  plots.  These  rows  were  33  hills  long  and  were 

'Strictly  speaking,  the  High  Yield  and  Low  Yield  strains  should  perhaps  be  re- 
ferred to  as  representing  partial  pedigree  selection,  since  the  individual  pollen  parentage 
was  not  controlled. 


570 


BULLETIN  No.  271 


[November, 


planted  two  stalks  to  a  hill.  Every  tenth  row  was  planted  from  a  com- 
posite lot  of  seed  to  serve  as  a  check  row.  The  field  in  which  this  test 
was  planted  proved  to  be  lacking  in  uniformity  of  productiveness,  as 
evidenced  by  the  extremely  wide  fluctuations  in  yield.  The  range  in  the 
yield  of  the  check  rows  was  from  6.5  to  29.2  pounds  a  row.  However, 

TABLE  1. — YIELDS  OF  SELECTED  Rows  IN  THE  PRELIMINARY  EAR-ROW  TEST  OF  990 

EARS  OF  FOUNDATION  STOCK,  AND  THE  YIELDSJSF  THEIR 

CORRESPONDING  CHECK  Rows 


Parent  ears  selected 
for  high  yield 

Average  of 
two  nearest 
check  rows 

Parent  ears  selected 
for  low  yield 

Average  of 
two  nearest 
check  rows 

Ear  row 

No. 

Weight  of 
ear  corn 

Weight  of 
ear  corn 

Ear  row 

No. 

Weight  of 
ear  corn 

Weight  of 
ear  corn 

36  

Ibs. 
18.6 
20.0 
23.7 
21.0 
20.3 
22.7 
30.8 
26.5 
29.5 
22.1 
27.5 
20.3 
23.5 
20.5 
19.6 
20.2 
16.1 
18.4 
16.1 
24.4 
24.3 
23.3 
27.1 
31.0 
21.5 
14.3 
16.5 
20.3 
25.4 
35.6 
29.6 
26.6 
33.0 
18.5 
30.4 
32.6 
34.7 
26.3 
30.8 
29.6 

Ibs. 
17.1 
12.1 
13.3 
15.9 
13.1 
16.8 
16.8 
16.8 
19.2 
20.5 
18.4 
14.2 
15.0 
11.8 
15.9 
12.6 
11.1 
13.3 
9.0 
11.4 
18.7 
13.0 
19.2 
21.7 
14.5 
8.6 
10.1 
11.6 
18.5 
19.8 
12.2 
15.6 
25.9 
11.9 
22.1 
24.1 
27.5 
18.1 
20.3 
21.3 

19  

Ibs. 
7.5 
5.1 
10.4 
11.6 
7.6 
10.4 
9.5 
10.8 
11.5 
14.4 
16.6 
9.7 
7.3 
9.7 
9.1 
5.2 
7.7 
5.4 
9.2 
13.5 
10.8 
7.4 
7.5 
12.4 
12.4 
4.3 
4.7 
7.7 
7.8 
9.4 
16.6 
8.6 
15.2 
19.7 
10.3 
10.7 
18.5 
10.7 
14.5 
17.9 

Ibs. 
13.1 
17.1 
13.7 
13.3 
14.8 
11.9 
14.0 
16.8 
16.5 
20.5 
18.4 
14.2 
15.0 
11.8 
15.9 
11.1 
13.3 
8.7 
17.1 
19.6 
16.8 
13.0 
13.6 
17.2 
19.2 
12.9 
8.6 
12.9 
14.0 
18.5 
18.0 
15.6 
21.0 
15.8 
11.9 
18.6 
24.1 
16.3 
18.1 
21.3 

51  

34  

68  

46  

88  

67  

115  

97  

128  

108  

159  

141  

179  

154  

183  

166  

194  

195  

203  

202  

223  

222  

256  

255  

272  

271  

299  

294  

306  

338  

337  

367  

363  

383  

399  

453     

408  

471  

523  

534  

543  

549  

616  

576 

649  

604.. 

705  

651  

751  

717     .... 

774  

752 

807  

816  

854  

825  

876  

858 

899  

861 

908  

904 

931  

921     

974  

955 

993  

975 

1006  

984 

1027  

1007     

1058  

1047 

1065  

1059 

1087  

1088 

Average  

24.3 

16.2         !  Average  

10.5 

15.6 

1925]  SELECTING  CORN  FOR  YIELD  571 

forty  rows  were  selected  that  were  most  productive  as  judged  by  the 
nearest  check  rows,  and  in  similar  manner  40  rows  that  proved  to  be 
low  yielding  were  selected.  The  remnant  seed  from  the  ears  used  in 
planting  these  rows  was  taken  as  the  foundation  stock  for  the  High 
Yield  and  Low  Yield  strains  respectively. 

The  yields  of  these  80  selected  rows  in  1911,  together  with  the 
averages  of  the  corresponding  check  rows,  are  shown  in  Table  1. 
Altho  the  average  of  the  check  rows  was  almost  the  same  for  the  two 
selections — about  16  pounds — the  averages  of  the  ear-rows  selected  for 
High  Yield  and  for  Low  Yield  differed  widely,  being  24.3  and  10.5 
pounds  respectively. 

The  Breeding  Plots 

The  High  Yield  and  Low  Yield  breeding  plots  consisted  of  40  indi- 
vidual ear-rows  each.  The  rows  were  at  least  80  hills  long,  the  hills 
being  39.6  inches  apart.  The  seed  was  planted  three  grains  in  a  hill  and 
the  stand  thinned  to  two  stalks  a  hill  at  about  the  time  of  the  first  culti- 
vation. Every  fifth  row  was  planted  from  a  composite  lot  of  seed  to 
serve  as  a  check,  and  in  order  to  prevent  contamination  in  the  breed- 
ing all  plants  in  these  check  rows  were  emasculated  by  detasseling.  In 
the  breeding  rows,  all  the  plants  in  alternate  halves  of  alternate  rows 
were  also  detasseled,  thereby  excluding  all  self-fertilization  and  prac- 
tically all  sister-brother  combinations  between  plants  in  the  same  row. 

Shortly  before  harvest  time  each  year,  a  search  was  made  in  the 
breeding  plots  for  the  most  desirable  plants  from  which  to  obtain  seed 
for  the  following  year.  The  most  vigorous  plants,  with  erect,  sturdy 
stalks  and  well-developed  ears  and  as  free  as  possible  from  disease,  were 
tagged  in  the  detasseled  portion  of  every  breeding  row.  At  harvest,  the 
crop  from  each  row  was  weighed  separately.  In  the  High  Yield  plot 
the  tagged  ears  from  the  ten  highest-producing  rows  were  saved  and 
from  the  Low  Yield  plot  those  from  the  ten  lowest-yielding  rows  were 
retained.  A  germination  test  and  subsequent  inspection  finally  deter- 
mined the  four  best  ears  from  each  of  the  ten  selected  rows  in  each  plot, 
which  constituted  the  forty  ears  with  which  to  carry  on  the  plot  the  fol- 
lowing year.  An  attempt  was  made  to  tag  only  the  best  plants  impar- 
tially in  both  the  High  Yield  and  the  Low  Yield  breeding  plots,  in  order 
that  selection  would  be  based  entirely  upon  the  yielding  capacity  of  the 
row,  the  two  plots  having  equal  opportunity  from  the  standpoint  of  the 
vigor  of  the  parent  plants. 

Pedigree  records  were  kept  in  such  manner  as  to  permit  tracing 
the  maternal  ancestry  of  every  seed  ear  planted  thruout  the  ten  genera- 
tions of  the  experiment. 

SPECIAL  HIGH  YIELD  STRAIN 

This  strain  originated  from  the  High  Yield  plot  described  above, 
after  the  work  had  been  under  way  for  five  years.  It  represents  an 


572 


BULLETIN  No.  271 


[November, 


attempt  to  overcome  in  some  degree  the  obstacle  to  controlled  breeding 
presented  by  the  open-pollinating  habit  of  the  corn  plant.  Altho  seed 
selected  each  year  for  high  yield  is  confined  to  the  highest-yielding  rows, 
this  seed  may  receive  the  inheritance  of  very  inferior  stock  thru  fertiliza- 
tion by  pollen  from  lower-yielding,  unselected  rows. 

With  the  Special  High  Yield  strain,  greater  control  was  exercised 
over  the  pollen  parent.  The  plan  is  based  on  the  use  of  remnants  of 
tested  seed  ears  and  follows  essentially  the  system  devised  by  Williams11 
of  the  Ohio  Experiment  Station.  An  ear-row  test  plot  and  a  mating  plot 
were  planted  each  year.  The  ear-row  test  plot  contained  80  rows  planted 
from  80  individual  ears  produced  in  the  mating  plot  of  the  preceding 
year  and  contained  also  20  check  rows  interspersed  at  five-row  inter- 
vals. Remnants  of  the  nine  most  productive  seed  ears  as  determined 
by  this  test  were  carried  into  the  mating  plot  the  year  following. 
This  mating  plot  was  made  up  of  12  rows,  8  of  which  were  planted 
from  individual  seed  ears  and  were  detasseled.  The  other  4  rows 
were  planted  from  a  single  ear  and  were  allowed  to  produce  pollen  for 
the  entire  plot.  In  harvesting  the  mating  plot,  80  ears  were  chosen  from 
the  detasseled  rows  to  be  tested  in  the  ear-row  plot  of  the  following  year. 

In  order  to  prevent  the  alternation  of  two  separate  strains  in  this 
system,  the  ear  from  which  the  four  pollen-producing  rows  were  to  be 
planted  was  reserved  for  use  in  the  mating  plot  the  second  year  after 
its  selection.  In  getting  the  system  started  it  was  necessary  to  modify 
it  slightly  by  planting  the  pollen-producing  rows  with  seed  from  the 
same  ear  two  years  in  succession. 

RESULTS:    YIELDS  OF  THE  VARIOUS  STRAINS 

Since  the  breeding  plots  for  the  High  Yield  and  Low  Yield  strains, 
as  well  as  for  the  Non-pedigree  strain,  were  isolated  in  order  to  prevent 
contamination  from  other  pollen,  it  was  impossible  to  make  any  accurate 

TABLE  2. — AVERAGE  ANNUAL  YIELDS  OF  THE  VARIOUS  STRAINS  IN  THE  YIELD  TEST  PLOT 

Bushels  per  acre 


Year 

High 

Yield 
strain 

Low 
Yield 
strain 

Non- 
pedigree 
strain 

Special 
High 
Yield 
strain 

Reid 
Yellow 
Dent 

1913... 

41  3 

38  0 

36  7 

37  5 

1914  

58  9 

55  1 

60  3 

54  3 

1915  

58  3 

52  7 

^6  0 

54  6 

1916  

29  9 

20  3 

28  6 

27  5 

1917  

70  9 

64  3 

71  5 

61  3 

1918  

69  8 

58  3 

73  3 

72  5 

65  9 

1919  

77  9 

70  0 

73  2 

75  2 

61  7 

1920  

76.9 

60  9 

74  9 

79  1 

78  2 

1921  

68  8 

45  7 

61  2 

63  4 

61  1 

1922  

70.1 

52.6 

73.6 

72.7 

68.4 

1925~\ 


SELECTING  CORN  FOR  YIELD 


573 


comparison  of  the  relative  productiveness  of  the  strains  from  the  yields 
obtained  in  those  plots.  Composite  lots  of  seed  from  each  strain  were 
therefore  planted  each  year  in  a  yield  test  plot,  where  their  productive- 
ness could  be  compared  under  as  similar  conditions  as  possible.  In  the 
earlier  years  of  the  work  these  plots  were  duplicated,  and  in  later  years 
the  replications  were  increased  to  four.  In  addition  to  the  High  Yield, 
Low  Yield,  Non-pedigree,  and  Special  High  Yield  strains,  the  Station 
Strain  of  Reid  Yellow  Dent,  as  representative  of  a  standard,  high- 
yielding  variety,  was  also  included  for  the  sake  of  comparison.  A  sum- 
mary of  the  yields  of  these  various  strains  is  given  in  Table  2. 

In  attempting  to  measure  the  progress  that  may  have  resulted 
from  these  lines  of  selection,  two  methods  of  analysis  are  employed: 
(1)  the  annual  yields  of  the  various  strains  are  divided  into  two  five- 
year  periods  for  comparison;  and  (2)  a  graphic  and  algebraic  repre- 
sentation is  made  by  means  of  fitted  straight  lines. 

ANALYSIS  BY  FIVE-YEAR  PERIODS 

Dividing  the  ten  years  thru  which  the  test  continued  into  two 
periods  of  five  years  each,  a  measure  of  any  progressive  change  in  yield 
is  obtained  in  which  the  annual  fluctuations  are  largely  ironed  out.  A 
summary  of  these  comparisons  is  presented  in  Table  3. 

TABLE  3. — COMPARISONS  OF  YIELDS  OF  DIFFERENT  STRAINS,  BY  FIVE-YEAR  PERIODS 


Strains  compared 

Period 

Difference 
in  bushels 
per  acre 

Odds  that 
difference  is 
significant 

High  Yield  over  Low  Yield  

First  5  years.  . 

5.80 

>  9999:1 

High  Yield  over  Non-pedigree  

Second  5  years 
First  5  years  .  . 

15.17 
1.27 

>  9999:1 
3.1:1 

Non-pedigree  over  Low  Yield  

Second  5  years 
First  5  years  .  . 

1.42 
4.53 

3.4:1 
34.6:1 

Second  5  years 

13.75 

>  9999:1 

High  Yield  over  Special  High  Yield  

1918-1922 

.09 

1.1:1 

High  Yield  over  Reid  Yellow  Dent  

First  5  years.  . 
Second  5  years 

4.58 
6.85 

216:1 
37:1 

Non-pedigree  over  Reid  Yellow  Dent  .  .  . 

First  5  years.  . 
Second  5  years 

3.31 
5.43 

18:1 
18:1 

NOTE — The  statistical  measure  used  in  the  above  table  is  that  proposed  by  "Student" 
and  further  explained  as  to  its  adaptation  to  agronomic  work  by  Love  and  Brunson.4  The 
detailed  data  upon  which  this  table  is  based  are  given  in  Tables  A  to  F  of  the  Appendix. 

Comparing  the  High  Yield  with  the  Low  Yield  strain,  it  will  be 
observed  that  the  average  annual  difference  increases  from  5.80  bushels 
an  acre  in  the  first  five-year  period  to  15.17  bushels  in  the  second  five- 
year  period.  Both  these  differences  are  highly  significant.  The  increas- 


574  BULLETIN  No.  271  [November, 

ing  divergence  of  nearly  10  bushels  an  acre  between  the  means  of  these 
two  periods  shows  the  possibility  of  effectively  separating  superior  and 
inferior  strains  of  corn  from  an  ordinary  variety  by  this  means  of 
selection. 

In  each  of  the  same  two  periods  the  Non-pedigree  strain  produced 
almost  as  much  as  the  High  Yield.  Indeed  the  small  differences  cannot 
be  considered  statistically  significant  in  either  of  the  five-year  periods, 
as  shown  by  the  very  small  odds.  The  gain  of  the  High  Yield  over  the 
Non-pedigree  strain  is  negligible;  in  other  words,  there  was  practically 
no  change  in  the  relative.'  productiveness  of  the  strains.  Under  the  con- 
ditions of  this  experiment  at  least,  the  simpler  method  of  mass  selection 
carefully  carried  out  would  appear  to  be  as  effective  in  maintaining  an 
ordinary  variety  of  corn  at  a  high  level  of  production  as  is  the  more 
complicated  and  more  expensive  method  of  the  pedigree  ear-row  plot. 

The  increases  of  the  Non-pedigree  over  the  Low  Yield  strain  for 
the  two  periods  are  very  similar  to  the  corresponding  differences  of  the 
High  Yield  over  the  Low  Yield  strain  noted  above.  The  close  corre- 
spondence of  the  Non-pedigree  strain  to  the  High  Yield  strain  would 
inevitably  lead  to  this  result. 

Since  the  Special  High  Yield  strain  was  not  started  until  the  fifth 
year  of  the  experiment,  we  can  compare  it  only  during  the  last  period. 
During  that  time  the  average  yields  of  the  High  Yield  strain  and  the 
Special  High  Yield  strain  were  practically  identical.  Thus  even  the 
more  complicated  system  of  the  Special  High  Yield  plot  resulted  in 
no  advantage. 

Both  the  High  Yield  and  Non-pedigree  strains  rather  consistently 
outyielded  the  Experiment  Station's  strain  of  Reid  Yellow  Dent,  and 
with  both  strains  the  increase  was  greater  during  the  second  period 
than  during  the  first  five  years.  The  increase  in  the  yield  of  the  High 
Yield  strain  over  Reid  Yellow  Dent  is  statistically  significant,  as  signifi- 
cance is  ordinarily  measured,  and  that  of  the  Non-pedigree  strain  over 
Reid  Yellow  Dent  is  possibly  significant.  If  we  may  consider  the  pro- 
ductiveness of  the  Reid  Yellow  Dent  to  have  remained  constant  thruout 
the  experiment,  the  slight  gains  of  the  High  Yield  and  Non-pedigree 
strains  on  this  basis  are  of  considerable  interest. 

ANALYSIS  BY  FITTED  STRAIGHT  LINES 

The  second  method  of  studying  the  results  of  the  experiment  in- 
volves the  fitting  of  straight  lines  to  the  annual  yields  by  the  method 
of  least  squares,  a  device  frequently  employed  in  statistical  analyses 
where  it  is  desired  to  show  trends.  The  equations  representing  the  lines 
are  calculated  in  the  form  y  =  mx  -f-  n,  where  y  equals  the  value  of  any 
ordinate  (yield);  x  equals  the  value  of  any  abscissa  (crop  year);  n,  the 
y-intercept;  and  m,  the  slope  of  the  line.  By  using  the  annual  yields 
displayed  in  Table  2,  the  following  equations  were  calculated. 


1925~\ 


SELECTING  CORN  FOR  YIELD 


575 


EQUATIONS  FOR  STRAIGHT  LINES 
Tenr-Year  Results 

High  Yield y  =  46.8873  +  3.4206  x 

Low  Yield y  =  44.9800  +  1.5133  x 

Non-pedigree y  =  45.4254  +  3.4455  x 

Reid  Yellow  Dent y  =  42.0254  +  3.3388  x 

Five-Year  Results 

High  Yield y  =  74.4000  —  0.8500  x 

Special  High  Yield y  =  74.8600  —  1.1400  x 

The  annual  yields,  together  with  their  fitted  straight  lines,  are 
shown  graphically  in  Figs.  1  and  2.  It  may  be  observed  that  the  straight 
lines  representing  the  High  Yield  and  the  Low  Yield  strains  show  a  pro- 
nounced divergence.  On  the  other  hand,  the  lines  for  the  High  Yield 


so 


60 


0  SO 


10 


High 

Lot*  l/ield 
Non-pedigree       Q  — — 


1913 


191-4        1915 


1916 


1917 


1913 


1919 


I9SO       /92I        1922 


FIG.  1. — FITTED  STRAIGHT  LINES  FOR  HIGH  YIELD,  Low  YIELD,  AND 
NON-PEDIGREE  CORN  SELECTIONS 

strain  and  the  Non-pedigree  strain  are  practically  parallel,  with  the 
former  showing  the  higher  yields  thruout.  The  lack  of  divergence  be- 
tween these  lines  suggests  that  perhaps  the  High  Yield  strain  gained  a 
slight  superiority  as  a  result  of  the  first  selection  by  the  preliminary 
ear-row  test,  and  maintained  this  advantage  thereafter.  In  Fig.  2  the 
straight  lines  representing  the  High  Yield  strain  and  the  Special  High 


576 


BULLETIN  No.  271 


[November, 


Yield  strain  are  nearly  identical,  indicating  little  difference  in  their 
relative  performance. 


DIRECTION  OF  STRAIGHT  LINES 

Mean  annual  divergence, 
Relative  slope         bushels  per  acre 

3.4206  1.9073 

1.5133 

3.4206  0.0249 

3.4455 

3.4206  0.0818 

3.3388 

3.4455  0.1067 

3.3388 

0.2900 


Strain 

High  Yield 

Low  Yield 

High  Yield 

Non-pedigree 

High  Yield 

Reid  Yellow  Dent. 

Non-pedigree 

Reid  Yellow  Dent 

High  Yield  (5  years  only) —0.8500 

Special  High  Yield  (5  years  only) —1.1400 


eo 


70< 


60 


£ 

$™ 


High  yield 
Spec/a 


Expressing  these  results  numerically  rather  than  graphically,  and 
comparing  the  relative  slopes  in  terms  of  mean  annual  divergence,  we 

find  a  divergence  between  the  High 
and  Low  Yield  strains  which  re- 
duced to  the  average  annual  basis 
amounts  to  1.91  bushels  an  acre. 
In  contrast  to  this,  with  the  slopes 
of  the  High  Yield  and  the  Non- 
pedigree  lines  almost  identical,  the 
mean  annual  divergence  is  only  .02 
bushels  an  acre.  Comparing  the 
High  Yield  with  Reid  Yellow  Dent, 
an  average  yearly  gain  of  .08 
bushels  an  acre  is  observed.  A 
mean  annual  divergence  of  nearly 
.11  bushels  an  acre  is  noted  in  a 
comparison  of  the  slopes  of  the 
Non-pedigree  and  Reid  Yellow 
Dent  strains.  The  relative  slopes 
of  the  High  Yield  and  the  Special 
High  Yield  strains  indicate  that 
the  Special  strain,  in  comparison 
with  the  High  Yield  strain,  was 
losing  ground  at  the  rate  of  .29 
bushels  an  acre  yearly. 

In  general,  the  method  of  study- 
ing the  data  by  fitted  straight  lines 
bears  out  in  a  striking  way  the 

conclusions  reached  in  the  preceding  method  of  analysis,  where  the  re- 
sults of  first  and  second  five-year  periods  are  compared. 


eo 


10 


I9t8         /9I9         1920        I92/        J928 

FIG.    2. — ANNUAL    YIELDS    AND    FITTED 

STRAIGHT   LINES   FOR   HIGH   YIELD, 

Low  YIELD,  AND  NON-PEDIGREE 

CORN  SELECTIONS 


1925~\  SELECTING  CORN  FOR  YIELD  577 

DISCUSSION 

The  Non-pedigree  strain  was  planned  originally  to  represent  the 
productiveness  of  the  foundation  stock  and  so  furnish  a  basis  for  judg- 
ing the  performance  of  the  pedigreed  strains.  For  this  purpose,  the 
yielding  capacity  of  the  Non-pedigree  strain  should  have  remained  con- 
stant for  the  duration  of  the  experiment.  It  is  observed,  however,  that 
there  is  a  slight  upward  trend  of  the  Non-pedigree  strain  when  com- 
pared with  Reid  Yellow  Dent.  The  superiority  of  the  Non-pedigree 
strain  over  Reid  Yellow  Dent  increased  from.  3.31  bushels  an  acre  dur- 
ing the  first  five-year  period  to  5.43  bushels  during  the  second  five-year 
period.  Similarly,  the  comparative  slopes  of  the  fitted  straight  lines 
show  an  increasing  divergence  of  the  Non-pedigree  strain  and  Reid 
Yellow  Dent  amounting  to  an  average  annual  increase  of  about  .11 
bushel  an  acre.  Altho  the  number  of  comparisons  is  too  small  to  make 
this  slight  improvement  very  significant,  it  would  seem  that  the  pro- 
ductive capacity  of  the  Non-pedigree  strain  probably  was  slightly  raised 
by  good  practices  of  mass  selection. 

In  the  ear-row  selections  a  very  pronounced  divergence  between 
the  High  Yield  and  the  Low  Yield  strains  occurred.  Altho  the  High 
Yield  strain  thruout  the  experiment  yielded  slightly  more  than  the  Non- 
pedigree  strain,  the  performances  of  the  two  strains  were  remarkably 
parallel.  This  forces  the  conclusion  that  the  divergence  between  the 
High  Yield  and  the  Low  Yield  strains  was  due  mainly  to  a  decrease  in 
the  yielding  capacity  of  the  latter.  Apparently  ear-row  breeding  pro- 
duced in  the  Low  Yield  strain  an  effect  comparable  to  the  changes 
produced  in  the  physical  and  chemical  properties  of  the  corn  plant  by 
this  method  of  breeding,  but  in  the  High  Yield  selection  it  failed  to 
cause  any  significant  change.  The  modified  method  of  the  Special  High 
Yield  plot  was  equally  ineffective  in  the  five  years  of  its  trial. 

The  reason  for  this  failure  to  increase  productiveness  is  not  alto- 
gether clear.  In  part,  it  may  be  related  to  soil  variability  and  the  con- 
sequent difficulty  of  accurately  determining  the  rows  of  highest  yielding 
capacity,  but  this  difficulty  should  apply  equally  in  the  Low  Yield  selec- 
tion, where  distinct  progress  was  made  in  decreasing  the  yield.  Again, 
the  fact  that  a  given  factorial  complex  that  makes  for  a  high  yield  one 
season  may  not  fit  the  conditions  of  the  following  season  should  also 
apply  to  the  Low  Yield  selection,  altho  perhaps  in  a  less  degree.  Prob- 
ably one  of  the  serious  limitations  in  breeding  for  high  production  by 
ear-to-row  selection  lies  in  the  effects  of  the  unavoidable  close  breeding 
in  a  small  plot.  The  great  mass  of  available  evidence  concerning  in- 
breeding in  corn  points  consistently  toward  lowered  yields  whenever 
corn  undergoes  inbreeding.  Altho  precautions  against  inbreeding  were 
taken,  such  as  systematically  distributing  over  the  plot  seed  ears  from 
a  parent  row,  and  detasseling  all  plants  from  which  the  seed  ears  were 
to  be  selected,  it  was  inevitable  that  much  close  breeding  should  have 


578  BULLETIN  No.  271  [November, 

taken  place  where  four  rows  in  any  year  traced  back  to  a  single  row  of 
the  previous  year. 

The  slight  superiority  of  the  High  Yield  strain  over  the  Non-ped- 
igree strain  appears  to  have  been  present  from  the  first  and  in  all  proba- 
bility was  the  result  of  the  initial  selection  of  the  forty  remnant  ears 
from  the  foundation  stock  based  on  their  performance  in  the  preliminary 
ear-row  test.  No  further  increase  in  productiveness  over  that  of  careful 
mass  selection  was  obtained  during  ten  years  of  ear-to-row  breeding. 

CONCLUSIONS 

The  outcome  of  this  investigation  leads  to  two  conclusions  con- 
cerning practical  methods  of  corn  breeding: 

1.  Continuous  selection  by  means  of  the  ear-row  breeding  plot 
cannot  be  recommended  as  a  means  of  increasing  the  yield  of  a  well- 
adapted  variety  of  corn. 

2.  By  continuous  mass  selection  the  yield  of  a  well-adapted  variety 
of  corn  can  be  maintained  and  perhaps  somewhat  increased. 

The  practical  recommendation  to  the  corn  grower  who  desires  to 
maintain  the  productiveness  of  his  crop  on  a  high  plane,  or  possibly  to 
increase  his  yields,  is  to  use  mass  selection  as  the  most  effective 
simple  method  of  selecting  corn  for  yield.  For  a  more  complete  dis- 
cussion of  such  method  the  reader  is  referred  to  Circular  28413  of  this 
Station,  in  which  the  details  of  the  method  are  described. 


.7925]  SELECTING  CORN  FOR  YIELD  579 


LITERATURE  CITED 

1.  HAYES,  H.  K.,  AND  ALEXANDER,  LEE 

1924.  Methods  of  corn  breeding.   Minn.  Agr.  Exp.  Sta.  Bui.  210. 

2.  HUME,  A.  N. 

1919.  Corn  families  of  South  Dakota.  S.  Dak.  Agr.  Exp.  Sta.  Bui.  186. 

3.  KlESSELBACH,  T.  A. 

1916.  Recent  developments  in  our  knowledge  concerning  corn.   Neb.  Corn.  Imp. 
Assoc.  Ann.  Rpt.  1916,  1542. 

4.  LOVE,  H.  H.,  and  BRUNSON,  A.  M. 

1924.    Student's  method  for  interpreting  paired  experiments.    Jour.  Amer.  Soc. 
Agron.,  16,  60-68. 

5.  MONTGOMERY,  E.  G. 

1909.  Experiments  with  corn.    Neb.  Agr.  Exp.  Sta.  Bui.  112. 

6.  NOLL,  CHARLES  F. 

1916.  Experiments  with  corn.   Pa.  Agr.  Exp.  Sta.  Bui.  139. 

7.  RICKEY,  FREDERICK  D. 

1922.  The  experimental  basis  for  the  present  status  of  corn  breeding.    Jour. 
Amer.  Soc.  Agron.,  14,  1-17. 

8.  SMITH,  LOUIE  H. 

1908.  Ten  generations  of  corn  breeding.    111.  Agr.  Exp.  Sta.  Bui.  128. 

9.  SMITH,  LOUIE  H. 

1909.  The  effect  of  selection  upon  certain  physical  characters  in  the  corn  plant. 

111.  Agr.  Exp.  Sta.  Bui.  132. 

10.  STUDENT 

1908.  The  probable  error  of  a  mean.    Biometrica  6,  1-25. 

11.  WILLIAMS,  C.  G. 

1907.  Corn  breeding  and  registration.   Ohio  Agr.  Exp.  Sta.  Cir.  66. 

12.  WILLIAMS,  C.  G.,  AND  WELTON,  F.  A. 

1915.  Corn  experiments.  Ohio  Agr.  Exp.  Sta.  Bui.  282. 

13.  WOOD  WORTH,  C.  M. 

1924.  A  program  of  corn  improvement.    111.  Agr.  Exp.  Sta.  Cir.  284. 


APPENDIX 

The  tables  in  this  Appendix  show  the  annual  yields  of  the  plots  in 
the  variety  tests,  which  were  planted  with  a  composite  of  seed  produced 
in  the  breeding  plots  the  previous  year. 

For  the  earlier  years  of  the  work  (1913-16),  when  the  plots  were 
only  duplicated,  each  yield  shown  in  these  tables  represents  one  plot. 
In  the  later  years  (1917-21)  each  strain  was  represented  by  four  plots 
and  each  yield  is  the  average  of  two  plots  from  two  different  series. 
For  1922  each  yield  represents  but  a  single  plot. 


TABLE  A.— 


First  five  years 

Second  five  years 

Year 

High 
Yield 

Low 
Yield 

Gain  H.Y. 
over  L.Y. 

Year 

High 
Yield 

Low 
Yield 

Gain  H.Y. 
over  L.Y. 

1913  

43.7 
39.0 

69.1 

48.8 

61.5 
55.1 

25.6 
34.1 

72.5 
69.3 

42.7 
33.3 

65.6 
44.6 

56.0 
49.4 

17.0 
23.5 

67.9 
60.7 

1.0 
5.7 

3.5 
4.2 

5.5 
5.7 

8.6 
10.6 

4.6 
8.6 

1918  

72.2 
67.3 

80.8 
75.1 

78.9 
74.8 

73.7 
63.8 

69.6 
70.7 

59.2 
57.5 

72.0 
68.1 

62.1 

59.7 

50.6 
40.8 

55.2 
50.0 

13.0 
9.8 

8.8 
7.0 

16.8 
15.1 

23.1 
23.0 

14.4 

20.7 

1914  

1919  

1915  

1920  ' 

1916  

1921  

1917  

1922  

Mean  

51.87            46.07              5.80 
2.67 
2.17 
>  9999:1 

Mean  

72.69            57.52             15.17 
5.47 
2.77 
>9999:1 

«r  

Z  

Odds  

Odds  

TABLE  B. — HIGH  YIELD  VERSUS  NON-PEDIGREE 
(Bushels  per  acre) 


First  five  years 

Second  five  years 

Year 

High 
Yield 

Non- 
pedigree 

Gain  H.Y. 
over  N.P. 

Year 

High 
Yield 

Non- 
pedigree 

Gain  H.Y. 
over  N.P. 

1913  

43.7 
39.0 

69.1 
48.8 

61.5 
55.1 

25.6 
34.1 

72.5 
69.3 

36.3 
37.1 

61.2 

59.3 

55.9 
56.0 

27.3 
29.9 

75.1 
67.9 

7.4 
1.9 

7.9 
-10.5 

5.6 
-.9 

-1.7 
4.2 

-2.6 
1.4 

1918  

72.2 
67.3 

80.8 
75.1 

78.9 
74.8 

73.7 
63.8 

69.6 
70.7 

69.6 
77.0 

77.4 
69.1 

78.2 
71.7 

67.0 

55.5 

75.4 
71.8 

2.6 
-9.7 

3.4 
6.0 

.7 
3.1 

6.7 
8.3 

-5.8 
-1.1 

1914 

1919  

1915  

1920  

1916  

1921....... 

1917 

1922  

51.87            50.60              1.27 
5.26 
.24 
3.1  :  1 

Mean  

72.69            71.27              1.42 
5.36 
.27 
3.4:1 

z  

Odds  

Odds  

582 


BULLETIN  No.  271 


[November, 


TABLE  C. — NON-PEDIGREE  VERSUS  Low  YIELD 
(Bushels  per  acre) 


First  five  years 

Second  five  years 

Year 

Non- 
pedigree 

Low 
yield 

Gain  N.P. 
over  L.Y. 

Year 

Non- 
pedigree 

Low 
yield 

Gain  N.P. 
over  L.Y. 

1913  

36.3 
37.1 

61.2 
59.3 

55.9 
56.0 

27.3 
29.9 

75.1 
67.9 

42.7 
33.3 

65.6 
44.6 

56.0 
49.4 

17.0 
23.5 

67.9 
60.7 

-6.4 
3.8 

-4.4 
14.7 

-.1 
6.6 

10.3 

6.4 

7.2 
.    7.2 

1918  

69.6 
77.0 

77.4 
69.1 

78.2 
71.7 

67.0 

55.5 

75.4 
71.8 

59.2 
57.5 

72.0 
68.1 

62.1 

59.7 

50.6 
40.8 

55.2 
50.0 

10.4 
19.5 

5.4 
1.0 

16.1 

12.0 

16.4 
14.7 

20.2 
21.8 

1914  

1919  

1915 

1920  ... 

1916 

1921 

1917 

1922     .  .  . 

50.60             46.07             4.53 
6.16 
.73 
34.6:1 

•       71.27            57.52             13.75 
6.32 
2.18 
>99°9:1 

z  

Odds  

Odds  

TABLE  D. — HIGH  YIELD  VERSUS  SPECIAL  HIGH  YIELD 
(Bushels  per  acre) 

Second  five  years 


Year 

High 
Yield 

Special 
High  Yield 

Gain  H.Y. 
overS.H.Y. 

1918  

72.2 

68.9 

3.3 

1919  

67.3 
80.8 

76.2 
76.8 

-8.9 

4  0 

1920  

75.1 

78.9 

73.6 
82.2 

1.5 
-3.3 

1921  

74.8 

73.7 

76.0 
66.9 

-1.2 
6.8 

1922  

63.8 
69.6 

59.9 
74.2 

3.9 
-4.6 

70.7 

71.3 

-.6 

Mean  

72.69 

72.60 

.09 

a  

4.51 

z  

.02 

Odds.  .  . 

1.1  :  1 

7925] 


SELECTING  CORN  FOR  YIELD 


583 


TABLE  E. — HIGH  YIELD  VERSUS  REID  YELLOW  DENT 
(Bushels  per  acre) 


First  five  years 

Second  five  years 

Year 

High 

Yield 

Reid  Yellow 
Dent 

Gain  H.Y. 
over  R.Y.D. 

Year 

High 
Yield 

Reid  Yellow 
Dent 

Gain  H.Y. 
over  R.Y.D. 

1913 

43.7 
39.0 

69.1 

48.8 

61.5 

55.  1 

25.6 
34.1 

72.5 
69.3 

42.7 
32.3 

58.7 
49.9 

53.2 
56.0 

23.4 
31.5 

65.7 
59.5 

1.0 
6.7 

10.4 
-1.1 

8.3 
-0.9 

2.2 
2.6 

6.8 
9.8 

1918  

72.2 
67.3 

80.8 
75.1 

78.9 
74.8 

73.7 
63.8 

69.6 
70.7 

64.5 
67.3 

61.7 
57.3 

81.3 

78.8 

52.7 
62.3 

67.9 
64.6 

7.7 
0.0 

19.1 
17.8 

-2.4 
-4.0 

21.0 
1.5 

1.7 
6.1 

1914     .     ... 

1919  

1915        

1920  

1916          

1921  

1917 

1922  

51.87            47.29              4.58 
4.11 
1.11 
216  :  1 

Mean  

72.69            65.84              6.85 
8.81 
.78 
37:1 

z  

Odds  

Odds  

TABLE  F. — NON-PEDIGREE  VERSUS  REID  YELLOW  DENT 
(Bushels  per  acre) 


First  five  years 


Year 

Non- 
pedigree 

Reid  Yellow 
Dent 

Gain  N.P. 
over  R.Y.D. 

Year 

Non- 
pedigree 

Reid  Yellow 
Dent 

Gain  N.P. 
over  R.Y.D. 

1913  

36.3 

42.7 

-6.4 

1918  

69.6 

64.5 

5  1 

1914  

37.1 
61.2 

32.3 
58.7 

4.8 
2.5 

1919  

77.0 
77.4 

67.3 
61.7 

9.7 
15  7 

1915  

59.3 
55.9 

49.9 
53.2 

9.4 
2.7 

1920  

69.1 

78.2 

57.3 
81.3 

11.8 
-3  1 

1916          .    .. 

56.0 
27  3 

56.0 
23  4 

0.0 

3  9 

1921     

71.7 
67  0 

78.8 
52  7 

-7.1 
14  3 

1917  

29.9 
75.1 

31.5 
65.7 

-1.6 
9  4 

1922  

55.5 
75  4 

62.3 
67  9 

-6.8 
7  5 

67.9 

59.5 

8.4 

71.8 

64.6 

7.2 

Mean  

50  60 

47.29 

3.31 

71  27 

65  84 

5  43 

a  

4.83 

7.94 

70 

68 

Odds  

29:  1 

Odds  

29:1 

Second  five  years 


AUTHOR  INDEX 


585 


AUTHOR  INDEX 


PAGE 

Bonnen,  C.  A.,  and  Eauchenstein, 
Emil.  Successful  Threshing 
Ring  Management 373-404 

Brunson,  Arthur  M.,  and  Smith, 
Louie  H.  An  Experiment  in 
Selecting  Corn  for  Yield  by 
the  Method  of  the  Ear-Row 
Breeding  Plot 567-84 

Case,  H.  C.  M.,  and  Myers,  K.  H. 
Cattle  Feeding  in  Relation  to 
Farm  Management 213-44 

Crawford,  C.  W.,  and  Edmonds, 
J.  L.  Feeding  Purebred 
Draft  Fillies 245-60 

Davidson,  F.  A.  Measuring  the 
Breeding  Value  of  Dairy 
Sires  by  the  Records  of  Their 
First  Few  Advanced  Registry 
Daughters 543-66 

Davidson,  F.  A.,  Overman,  O.  R., 
and  Sanmann,  F.  P.  Relation 
of  Solids  in  Milk  to  Fat  and 
Specific  Gravity  in  the 
Milk 261-72 

Dungan,  G.  H.,  Koehler,  Benja- 
min, and  Holbert,  J.  R.  Fac- 
tors Influencing  Lodging  in 
Corn 309-72 

Dungan,  G.  H.,  McKinney,  H.  H., 
and  .Webb,  R.  W.  Wheat 
Rosette  and  Its  Control. .  .273-96 

Edmonds,  J.  L.,  and  Crawford, 
C.  W.  Feeding  Purebred 
Draft  Fillies 245-60 

Gaines,  W.  L.,  and  Nevens,  W.  B. 
The  Sunflower  as  a  Silage 
Crop :  Composition  and  Yield 
at  Different  Stages  of  Ma- 
turity   405-56 

Harland,  M.  B.,  and  Wimer,  D.  C. 
The  Cultivation  of  Corn: 
Weed  Control  vs.  Moisture 
Conservation 173-96 

Holbert,  J.  R.,  Koehler,  Benja- 
min, and  Dungan,  G.  H.  Fac- 
tors Influencing  Lodging  in 
Corn 309-72 

Kammlade,  W.  G.,  and  Mackey, 
A.  K.  The  Soybean  Crop  for 
Fattening  Western  Lambs 

..197-212 


PAGE 

Keith,  M.  Helen.  Bibliography 
of  Researches  Bearing  on  the 
Composition  and  Nutritive 
Value  of  Corn  and  Corn 
Products 1-152 

Koehler,   Benjamin,   Dungan,    G. 
H.,  and  Holbert,  J.  R.    Fac-  * 
tors  Influencing  Lodging  in 
Corn 309-72 

Mackey,  A.  K.,  and  Kammlade, 
W.  G.  The  Soybean  Crop 
for  Fattening  Western 
Lambs 197-212 

McKinney,  H.  H.,  Webb,  R.  W., 
and  Dungan,  G.  H.  Wheat 
Rosette  and  Its  Control. .  .273-96 

Myers,  K.  H.,  and  Case,  H.  C.  M. 
Cattle  Feeding  in  Relation- 
ship to  Farm  Management. 2 13-44 

Nevens,  W.  B.,  and  Gaines,  W.  L. 
The  Sunflower  as-  a  Silage 
Crop:  Composition  and  Yield 
at  Different  Stages  of  Ma- 
turity   405-56 

Overman,  O.  R.,  Davidson,  F.  A., 
and  Sanmann,  F.  P.  Relation 
of  Solids  in  Milk  to  Fat  and 
Specific  Gravity  of  the 
Milk 261-72 

Plunkett,  O.  A.,  and  Stevens, 
Frank  Lincoln.  Tulip  Blos- 
som Blight 297-308 

Rauchenstein,  Emil,  and  Bonnen, 
C.  A.  Successful  Threshing 
Ring  Management 373-404 

Ross,  H.  A.  The  Marketing  of 
Milk  in  the  Chicago  Dairy 
District 457-540 

Sanmann,  F.  P.,  Overman,  O.  R., 
and  Davidson,  F.  A.  Rela- 
tion of  Solids  in  Milk  to  Fat 
and  Specific  Gravity  in  the 
Milk 261-72 

Smith,  Louie  H.,  and  Brunson, 
Arthur  M.  An  Experiment 
in  Selecting  Corn  for  Yield 
by  the  Method  of  the  Ear- 
Row  Breeding  Plot 567-84 


583  AUTHOR  INDEX 

PAGE  PAGE 

Smith,  Raymond  S.    Experiments  Webb,  R.  W.,  McKinney,  H.  H., 

with    Subsoiling,    Deep    Till-  and  Dungan,  G.   H.     Wheat 

ing,    and    Subsoil    Dynamit-  Rosette  and  Its  Control. .  .273-96 

ing 153-72  Wimer,  D.  C.,  and  Harland,  M.  B., 

Stevens,      Frank      Lincoln,      and  The     Cultivation     of     Corn : 

Plunkett,  O.  A.     Tulip  Bios-  Weed    Control    vs.    Moisture 

som  Blight ,297-308  Conservation 173-96 


INDEX 


587 


INDEX 


(The  headings  in  capitals  are  subjects  of  entire  bulletins) 


PAGE 

Alfalfa  hay  vs.  soybean  hay  in 

feeding  lambs  .  : 201,  205 

Aplanobacter  stewarti 366 

Barley,  Literature  on  studies  of 

at  different  stages 452 

Black-bundle    disease,    cause    of 

broken  stalks  in  corn 333 

Blight,  see  Tulip  blossom  blight 
Bulls,  see  Dairy  sires 
Butterfat  market  in  Chicago  dis- 
trict   531-32,  540 

Buttermilk,  Consumption  in  Chi- 
cago   491-97 

Use  of  surplus  milk  for 521,  522 

Cane,  sugar,  Disease  of  similar  to 

wheat  rosette 283 

Cannery  refuse,  Bibliography  on 

feeding 132 

CATTLE  FEEDING  IN  EELA-  " 
TION     TO     FARM     MAN- 
AGEMENT   213-43 

Cost  of  producing  beef 219-33 

how  determined 220-21 

reduction  thru  use  of  rough- 
age   231-32 

relation       to       other       farm 

costs 232-33 

relative  importance  of  items 

of  expense ;  221-24 

variation         on          different 

farms 228-30 

variation       with       size       of 

cattle 225-28 

Necessary  margin   in 230-31 

Place  of   feeding   on   corn-belt 

farms 234-42 

effect  on  farm  as  a  whole. 241-42 

maintains  fertility 240-41 

reduces  cost  of  other  enter- 
prises   240 

utilizes  farm-raised  crops. 235-37 
utilizes    labor    often    wasted 

237-39 

Summary  of  study 215 

Cephalosporium   acrcmonium 

Corda 322-23,  333,  366,  369 

Cerealine    feed,    Bibliography   on 

feeding 132 

Cheese,  Price  of  milk  for. 528-30,  539 
Utilization     of     surplus     milk 
as  ...  ..521-22 


PAGE 
Chicago  dairy  district,  Expansion 

of • 469 

Factors      retarding      extension 

of 473-78 

increased  use  of  trucks. .  .476-78 
large    investments    in    coun- 
try   473-75 

limitation     of     direct     ship- 
ment   475-76 

Intensity  of  dairying  in  inner 

and  outer 478-79 

Milk  production  in 479-89 

seasonal       production       and 

price 487-89 

seasonal  variation 483-87 

variation      from      year      to 

year 480-83 

Regional  production  in 469-71 

Transportation  costs  in 471-73 

Chicago       cream,       Consumption 

of 489-500 

Chicago  maize  feed,  Bibliography 

on  feeding 132 

Chicago    milk    consumption,     As 

affected   by  price.... 503-10 

As  affected  by  temperature .  500-503 
In  different  sections  of  city. 490-93 

Long-time  trend  of 494-95 

Per  capita 489-90 

Ratio  of  pints  to  quarts. 490-92,  538 
Relation  of  to  consumption  of 

cream 492-93 

Seasonal  variation  in 495-98 

Variation  by  days  of  week. 498-500 
Chicago    milk    distribution,    Cost 

of 512-13 

Chicago  milk  distributors 463-69 

Bottle  exchange  of 467-69,  537 

Decrease  in  number  of 464 

Types  of 465-67 

Variation  in  size  of  companies  465 
Chicago    milk    prices,    Effect    of 

alternative   markets   on... 527-32 
Effect  of  on  consumption. .  .503-10 

Factors  determining 532-33 

Relation      of     to      prices      for 

cream 523-25 

Tables  showing 536-40 

Trend  of  in  Chicago 526-33 

Chicago  surplus  milk 510-35 

Amount  necessary  to  carry. . . .   519 


588 


INDEX 


PAGE 
Daily      variation      in      amount 

of 516-19 

Relation     between     prices     of 
sweet      cream      and      whole 

milk 523-25 

Relation  between  size  of  busi- 
ness and  amount  of 513-15 

Seasonal    variation   in    amount 

of 515-16 

Utilization  of 519-25 

Variation     in     from     year     to 

year 511-13 

Waste  of  surplus  skim  milk . .  522-23 
Clover,  Literature  on   studies  of 

at  different  stages 452 

Condensed    milk,    Utilization    of 

surplus  milk  as 521-22 

Condensery    prices    for    milk    in 

Chicago 527,  538 

CORN,  AN  EXPERIMENT  IN 
SELECTING  FOR  YIELD  BY 
THE  METHOD  OF  THE 
EAR-ROW  BREEDING  PLOT 

565-83 

Bibliography •„   579 

Conclusions 578 

Discussion  of 577-78 

Investigations     at    other    Sta- 
tions   567-68 

Plan  of  investigations 568-72 

Results 572-76 

Summary 566 

Corn,  Breeding  of,  see  Corn,  An 
experiment  in  selecting 
Comparison  of  nutritive  yields 

of  sunflowers  and 434-35 

Cultivation  of 173-96 

Literature    on    studies    of    at 

different  stages 449-52 

Lodging  of,  see  Lodging 
Root    systems    of,    Relation   to 
leaning    and    pulling    resist- 
ance   357-64 

CORN  AND  CORN  PRODUCTS, 
BIBLIOGRAPHY  ON  RE- 
SEARCHES BEARING  ON 
THE  COMPOSITION  AND 
NUTRITIVE  VALUE  OF...  1-151 
Analytical  determinations. .  .94-100 

Balance  experiments 138-39 

Books,  pamphlets,  and  articles 

on 150 

Chemical  composition  of,  Spe- 
cific effects  of 142^44 

Comparisons  of  white  and  yel- 
low corn 108 

Composition      of,       Conditions 

affecting 100-104 

Corn  breakfast   foods,  Studies 
of  .  .   106 


PAGE 

Corn  cobs,  Studies  of 107 

Corn  oil,  Studies  of 104 

Corn  pollen,  Studies  of 107 

Corn  proteins,  Studies  of 105 

Corn  starch,  Studies  of 106 

Corn  sugar,  Studies  of 106 

Digestion  experiments  with.  132-37 
Energy  metabolism  of  animals 

fed  on 139 

Energy  values  of 104 

Enzymic  digestion  of 104 

Feeding  tests  with 109-32 

Nutritive  value  of,  Studies  of 

conditions  affecting 139—42 

Other  studies  with  animals ....   149 
Physiological       and       anatomical 

effects  of 145-48 

Pop  corn,  Studies  of 106 

Silo,  Studies  of  processes  and 

agents  working  in 107 

Spoilage  of,  Studies  of 108 

Cost  accounting,  Plan  of  studies 

in  Hancock  county 218 

Study  of  in  beef  production219-43 
Value    of    in    analyzing    busi- 
ness   242-43 

Cream,  Butterfat  market  for.. 531-32 
Consumption  in  Chicago. .  .489-500 
Relation  between  prices  of 

whole  milk  and 523-25 

Utilization  of  surplus  milk  as  519 
CULTIVATION  OF  CORN. .  .173-96 
Early    experiments    on    depth, 
frequency,    and     root    prun- 
ing   ..177-78 

Experiments  on  free  growth  of 
weeds,  surface  scraping,  and 

shallow  cultivation 191-96 

Experiments  on  value  of  seed- 
bed   preparation,    irrigation, 

and  fertilizing 179-89,  191 

Need  no  greater  in  dry  years!83-84 

Purpose  of 175 

Shallow,  Advantages  of 175-77 

Summary  of  experiments 174 

DAIRY  SIRES,  MEASURING 
THE  BREEDING  VALUE  OF 
BY  THE  RECORDS  OF  THEIR 
FIRST  FEW  ADVANCED 
REGISTRY  DAUGHTERS  543-66 

Bibliography 565 

Conclusions 564—65 

Discussion  of  results 556-60 

Method,  Application  of 564 

Derivation  of 560-61 

Number  of  daughters  necessary 

to  measure  value  of  sire. . . .  548 
Outline  of  investigation 546-55 


INDEX 


589 


PAGE 

Smallest  number  of  daughters 
whose  production  will  ap- 
proximate that  of  large  num- 
ber   548-51 

Source  of  data 546 

Diplodia  zeae 3!14721>  333>  369 

Distillers '  grains,  Bibliography 
on  feeding 136 

Distillery  refuse,  Bibliography  on 

feeding 136 

Slop,  Bibliography  on  feeding  136 

Dynamite  for  subsoiling,  Cost  of  170 

Effect  on  subsoils 157 

Experiments   in  Kansas 157 

Experiments  on  Toledo  field.  161-67 

For  fruit  trees 158 

Practical  for  true  hardpan 165 

Ear-row  method  of  breeding,  see 
Corn,  An  experiment  in  select- 
ing 

ECONOMIC  FACTORS  IN  CAT- 
TLE FEEDING:  FEEDING 
IN  RELATION  TO  FARM 
MANAGEMENT 213-43 

Evaporated  milk,  Utilization  of 
surplus  milk  as 521-22 

EXPERIMENT  IN  SELECT- 
ING CORN  FOR  YIELD  BY 
THE  METHOD  OF  THE 
EAR-ROW  BREEDING  PLOT 
565-83 

FACTORS  INFLUENCING 
LODGING  IN  CORN 309-71 

Fairfield  experiment  field,  Culti- 
vation experiments  on 191 

Farm  management,  Cattle  feeding 
in  relation  to  .  .  218-i3 

Feed  costs,  Method  of  calculat- 
ing   208-11,  258-59 

Feeding,  Advantages  in  cattle . . .  243 

FEEDING  PUREBRED  DRAFT 
FILLIES 245-60 

Feeding  sovbeans  to  lambs . . .  197-211 

FILLIES,"  FEEDING  PURE- 
BRED DRAFT 245-60 

Development  of  fillies 255-56 

Feeds,  amounts  used 249-54 

cost  of 257-59 

kinds  of 248 

method    of    calculating    cost 

of  per  head 258-59 

Plan  of  experiment 247 

Shelter  and  care : 249 

Summary  of  experiment ...  246,  260 
Summary    of    previous    experi- 
ments   259-60 

Value  of  pasture 254—55 

Foot  rot  of  wheat 290 

See  Wheat  rosette 

Fruit  trees,  Effect  of  dynamiting 
subsoil  for  .  .  .  158 


PAGE 

Fusarium  moniliforme 

314-15,  333,  369 

Germ  oil  meal,  Bibliography  on 
feeding 136 

Gibberella  saubinetii 

328-32,  333,  337,  344,  369 

Gluten     feed,     Bibliography     on 

feeding 136 

Meal,  Bibliography  on  feeding  137 

Guernsey  milk  yields,  Age  correc- 
tion for 562 

Hancock  county,  Types  of  farm- 
ing in 217 

Cost  accounting  studies  in....  218 
Cattle-feeding    cost    studies    in 
219-43 

"Hardpan,"  So-called  in  Illinois 
not  true 165 

Hclminthosporium  sativum,  Ex- 
periments in  relationship  with 
wheat  rosette. .  .282,  283-92,  278-79 

Hessian  fly  injury,   Resemblance 

to  wheat  rosette 282 

Not  cause  of  rosette 283 

Hominy  chop,  feed,  and  meal, 
Bibliography  on  feeding 137 

Horses,  see  Fillies 

Irrigation,  Effect  of  on  weeds  and 
corn 187 

Jersey  milk  vields,  Age  correction 
for 563 

Kaffir  corn,  Literature  on  studies 
of  at  different  stages 452 

Kans.  Exp.  Sta.,  Experiments 
with  dynamiting  .  ; 157 

Lambs,  Fattening  with  soy- 
beans   197-211 

Limestone,  Effect  of  on  lodging 
in  corn 344-51 

Linseed  oil  meal  vs.  soybean  oil 
meal 203,  205-06 

LODGING  IN  CORN,  FACTORS 

INFLUENCING ....309-71 

Bibliography 371 

Comparisons  of  leaning  in  self- 
fertilized  strains 354-64 

Comparison    of   stalk   breaking 

in  self -fertilized  strains 364-69 

Methods  of  experiments. ..  .311-14 
Nonparasitic  factors  affecting 

differences  in  strains 334-35 

previous  cropping 339—44 

rate  of  planting 338-39 

soil  treatments 344—51 

time  of  planting 335-38 

yield 351-54 

Parasitic  factors,  Effect  of  on 
broken  stalks 

infected  seed 332-33 

starchy  scutellum-infected 

seed  .  334 


590 


INDEX 


PAGE 
Effect  of  on  leaning 

Cephalosporium 322-23 

Diplodium 314-21 

Fusarium 314—15 

Gibberella 328-32 

scutellum 323-28 

Summary 369-70 

Lucern,  Literature  on  studies  of 
at  different  stages 452 

Macon  county  experiment  on  in- 
fluence of  limestone  on  lodg- 
ing of  corn 345 

' '  Maize-cake, ' '  Bibliography  on 
feeding 137 

Maizena,  Bibliography  on  feeding  137 

MARKETING  OF  MILK  IN 
THE  CHICAGO  DAIRY  DIS- 
TRICT   457-540 

Conclusions 533-34 

MEASURING  THE  BREEDING 
VALUE  OF  DAIRY  SIRES 
BY  THE  RECORDS  OF  THEIR 
FIRST  FEW  ADVANCED 
REGISTRY  DAUGHTERS. 543-66 

Milk     dealers'     bottle     exchange 

467-69,  537 

Can  exchange 469 

Milk  distribution,  Cost  of 512-13 

Milk  drivers'  wage  in  Chicago. 512-13 

Milk  powder,  Utilization  of  sur- 
plus milk  as 521-22 

Milk  production,  marketing,  and 
consumption  in  Chicago  dairy 
district,  see  Chicago 

MILK,  RELATION  OF  SOLIDS 
IN  TO  FAT  AND  SPECIFIC 
GRAVITY  OF  THE  MILK. 261-71 

Bibliography 271 

Conclusions 270 

Plan  of  investigation 264-65 

Results 265-69 

Summary 269-70 

Milk  tank  car,  Use  of  in  Chi- 
cago district  .  .  .  .471-73,  476,  478 

Milk  yields,  Age  correction  fac- 
tors for 562-63 

Mosaic  disease,  Resemblance  of  to 
wheat  rosette 282-83,  291 

Nematode  disease  of  wheat,  Re- 
semblance of  to  wheat  rosette  282 

"New  corn  product,"  Bibliogra- 
phy on  feeding 137 

Nutrition  experiments  with  corn 
and  corn  products,  Bibliogra- 
phy on 109-49 

Oat  straw  vs.  soybean  straw  in 
feeding  lambs 206 

Oats,  Literature  on  studies  of  at 
different  stages 452 


PAGE 

Odin  experiment  field,  Plowing 
and  dynamiting  experiments 

at 158-61 

Ohio  Exp.  Sta.,  Plowing  experi- 
ments at 156 

Ophiobolus  graminis 275,  278 

Pa.  Exp.  Sta.,  Plowing  experi- 
ments at 156-57 

Pasteurizing  plants  in  Chicago . .  464 

Pasture,  Value  for  fillies 254-55 

Phytophthora  cactorum 306,  307 

Plowing,  Cost  of  deep 155,  170 

Effect    of    deep    on    drainage 

154,  166-67 

Experiments  in  Illinois 158-69 

summary  of 154 

Experiments  in  other  states.  156-57 

Purpose  of 155 

Pop  Corn,  Bibliography  on  stud- 
ies of  106 

RELATION  OF  SOLIDS  IN 
MILK  TO  FAT  AND  SPE- 
CIFIC GRAVITY  OF  THE 

MILK 261-71 

Ehisopus  spp 323 

Rock    phosphate,    Effect    of    on 

lodging  in  corn 345 

Rosette  disease,  see  Wheat  rosette 
Rye,  Literature  on  studies  of  at 

different  stages 452 

Scutellum    rot,    Influence    of    on 

breaking  in  corn  stalks. 333,  337 
Influence     of     on     leaning     in 

corn 323-28 

Silage,  Sunflower 405-55 

Silo,    Bibliography    on    processes 

and  agents  working  in 107 

Skim  milk,  Waste  of  surplus  in 

Chicago 522-23 

Sorghum,    Literature    on    studies 

of  at  different  stages 452 

SOYBEAN  CROP  FOR  FAT- 
TENING WESTERN  LAMBS 

197-211 

Calculating  cost  of  gains. .  .208— 11 

Ground  beans  vs.  whole 201 

Hay  vs.  alfalfa  hay 201,  205 

Hay  vs.  straw 203 

Meal     vs.     whole     or     ground 

beans 201-03,  205 

Oil    meal   vs.   linseed    oil    meal 

203,  205-06 

Plan  of  experiments 

199-200,  203-05 

Straw  vs.  oat  straw 206 

Summary    and    conclusions.... 

199,  206-08 

Subsoil,   Effect   of   tight  clay  on 
plants'   sensitiveness  to  drouth 
160,  163 


INDEX 


591 


Subsoiling,  see  Plowing 
SUBSOILING,  DEEP  TILLING, 
AND    SUBSOIL    DYNAMIT- 
ING, EXPERIMENTS  WITH 

153-70 

SUCCESSFUL         THRESHING 

RING   MANAGEMENT... 373-403 
SUNFLOWER    AS    A    SILAGE 
CROP:    Composition  and  Yield 
at     Different    Stages    of    Ma- 
turity   405-55 

Bibliography 454—55 

Comparative  yields  and  compo- 
sition of  sunflowers  and  corn 

' 434-35 

Composition  of  crop 429-34 

Fertility  removed  by 436-42 

Growth,    Mathematical    expres- 
sion of 415-29 

Objects  and  plan  of  investiga- 
tion .  .  . 408-11 

Review    of   previous    literature 

on 447-53 

Summary  and  conclusions. .  .445-47 
Thickness    of   planting,    Effect 

of 442-43 

Time  of  planting,  Effect  of.  .443-45 

Yield  of  crop 411-15 

as  ensiled 429-34 

indigestible  nutrients  .  .   .435-36 
Surplus     milk,     Problem     of     in 

Chicago 510-35 

Sweet  clover  pasture  for  fillies. 252-56 
Take-all    disease,    distinct    from 

rosette  of  wheat 275,  278,  282 

Temperature,   Effect   of   on   milk 

consumption  iu  Chicago. . .  .500-503 
Threshing,  Survey  of 
Acreages  threshed  by  machines 

of  various  sizes 377-78 

Organization  of  labor 385-88 

Proportionate   cost   of   to   pro- 
duction     375 

Summary  of  time  requirements  389 
Variation     in     labor     require- 
ments   379-84 

Threshing      machines,      Acreages 

threshed  by  various  sized. 377-78 
Advantages  of  large  and  small 

389-91 

Ownership     of     by     threshing 

rings 397-403 

Size  of  tractors  needed  for  vari- 
ous sized 378-79 


PAGE 

Threshing  ring  management,  La- 
bor  settlements   in 391-97 

Methods  of  securing  data  on . .   376 

Ownership  of  machines.  ..  .397-403 

written  agreements  for.. 401-403 

Summary  of  study  of 374 

Tilling,    deep,    Use    of    machine 

for 162-63 

See  also  Plowing 

Toledo  experiment  field,  Plowing 
and  dynamiting  experiments 
at 161-67 

Tractors,  Number  of  in  Illinois. .   375 
Ownership  of  in  threshing  rings  397 
Sizes    used   with   various   sized 
threshing  machines  .' .  .   .  .378-79 

Trucks,  Use  of  in  hauling  milk  to 
Chicago 476-78 

TULIP  BLOSSOM  BLIGHT. 297-307 

Causal  organism 301 

cultural  characters  of ....  305-306 

description  of 303-305 

taxonomic  position  of 306 

Influence  of  environment  on ...   301 

Inoculation  studies  of 301-03 

Recommendations  for 307 

Summary  of  study 307 

Symptoms  of 301 

Urbana  experiment  field,  Experi- 
ments on 

Cultivation 177-90,  191-96 

Lodging  of  corn 339-44,  345 

Plowing 167-70 

Weeds,  Effect  of  on  corn  yields  176-77 
Experiments    in,    see    Cultiva- 
tion of  corn 

Wheat,  Literature  on  studies  of 
at  different  stages 452 

WHEAT    ROSETTE    AND    ITS 

CONTROL .273-96 

Bibliography 296 

Cause  of 283-92 

Cell  inclusions 292 

Conclusions 295 

Control     by     resistant     varie- 
ties   292-95 

Crops  affected  by 277 

Distribution  of 275-76 

Losses  caused  by 276-77 

Resistant  varieties  of  wheat . . .  294 

Spread  of  disease 292 

Summary 274 

Symptoms 277-83 


I  Hi 


1927 


• 


•??  Ml 


UNIVERSITY  OF  ILLINOIS-URBANA 


